1. Field of Invention
The invention relates to a mechanism for forwardly and reversely feeding a recording medium, such as a sheet of paper.
2. Description of Related Art
A known image forming apparatus, such as a laser printer, includes a double-sided printing function for printing images on both sides of a sheet of paper. To form images on both sides of a sheet of paper, an image is first formed on one side thereof in an image forming unit. Thereafter, the sheet of paper is reversely fed again to the image forming unit where an image is formed on the other side thereof.
A reverse feeding mechanism for reversely feeding a sheet of paper is structured in the following manner. A sheet of paper having an image on one side thereof is held between a pair of reverse feedable rollers rotating in a forward direction. As the sheet of paper is fed to the rear end thereof, the reverse feedable rollers are rotated in a reverse direction with the sheet of paper being held by the reverse feedable rollers. Thus, the sheet of paper is reversely fed.
A mechanism for forwardly and reversely feeding a recording medium according to the invention may ensure the reliable and smooth rotation of reverse feedable rollers in a forward direction and a reverse direction. The mechanism according to the invention achieves significant manufacturing cost reduction, and running cost reduction, as well as endurance improvements.
In various embodiments of a drive mechanism for forwardly and reversely feeding a recording medium, the drive mechanism comprises an input transmission mechanism for transmitting a drive force from a motor, an output transmission mechanism for transmitting the drive force to the drive roller, an intermediate transmission mechanism for selectively transmitting the drive force from the input transmission mechanism to the output transmission mechanism in either a first direction or a second direction and a switching mechanism for moving the intermediate transmission mechanism to a first position to drive the output transmission mechanism in the first direction or a second position to drive the output transmission mechanism in the second direction.
In various embodiments of a method for driving a drive mechanism for forwardly and reversely feeding a recording medium, the method comprises the steps of transmitting a drive force from an input transmission mechanism, transmitting the drive force from the input transmission mechanism in either a first direction or a second direction by an intermediate transmission mechanism, outputting the drive force to a drive roller with an output transmission mechanism and moving the intermediate transmission mechanism to a first position to drive the output transmission mechanism in the first direction or a second position to drive the output transmission mechanism in the second direction by a switching mechanism.